Nineteen compounds isolated from Ranunculus sieboldii and Ranunculus sceleratus were tested for inhibitory effects on hepatitis B virus (HBV) and Herpes simplex virus type-1 (HSV-1). The results showed that apigenin 4'- O- alpha-rhamnopyranoside, apigenin 7- O- beta-glucopyranosyl-4'- O- alpha-rhamnopyranoside, tricin 7- O- beta-glucopyranoside, tricin, and isoscopoletin possessed inhibitory activity against HBV replication. Protocatechuyl aldehyde exhibited an inhibiting activity on HSV-1 replication. It is therefore suggested that further investigations on these bioactive compounds might be needed to discover and develop new antiviral agents.